The outlined experiments are proposed to (1) characterize how Ab1 is coupled to fibroblast growth factor receptor-1 (FGFR-1) signaling and (2) establish a role for FGFR-1 signaling through the Ab., Ras, and PlCgamma in lens development. In addition, an analysis of lens development using the transgeneic mice expressing the various alleles of Ab1 may identify specific protein interaction domains of Ab. involved in lens epithelial proliferation and differentiation.